Seasonal variation in incidence and outcomes of out of hospital cardiac arrest

Abstract

Out of hospital cardiac arrest (OHCA) remains a leading cause of mortality among adults in the United States. Environmental impact on incidence and outcomes of OHCA has not been fully investigated in recent years. Previous studies showed a possible increase in incidence and mortality in winter season and during seasons with temperature extremes. This study examines seasonal variation in incidence and outcomes of OHCA in the United States. Retrospective study of adult OHCA using the Nationwide Emergency Department Sample was carried out. Monthly incidence rate per 100,000 ED presentations was calculated. Survival rates for each month of admission were examined by hospital region. Multivariate analyses were conducted to determine the effect of the season and month of admission on survival. A total of 122,870 adult OHCA cases presented to emergency departments (EDs) in 2014 and were included. Average incidence of OHCA cases was 147 per 100,000 ED presentations. Overall survival rate in the study population was 5.6% (95% confidence intervals [CI] = 5.4%–5.9%). Patients had an average age of 65.5 (95% CI: 65.3–65.7) years and were mainly men (61.8%). Rates of OHCA presentations were highest during December and January (9.9% and 10.0%) while survival rates were lowest during December (4.6%) and highest in June (6.9%). Regional variation in OHCA outcomes was also noted with highest average survival rate in West (7.8%) and lowest in South (4.3%). After adjusting for confounders including region of hospital, Summer season (Ref: all other seasons), and more specifically month of June (Ref: all other months) were found to be positively associated with survival (OR 1.27, 95% CI [1.07–1.52], P -value = .008) and (OR 1.43, 95% CI [1.08–1.89], P -value = .012 respectively). Incidence and outcomes of out of hospital cardiac arrest presentations to the emergency departments in the United States have seasonal variation. Both incidence and mortality of OHCA increase during colder months, and survival is significantly higher in summer season or in June. Exploring how to use this variation to improve outcomes through refresher training of medical providers or through other mitigation plans is needed.

Debunking the July Effect in lung transplantation recipients

“… 20 Likewise, the higher occurrence of cardiac arrest during Q2-Q4 may be due to increased vasoconstriction, higher blood pressure, blood viscosity, and fibrinogen levels. 21 , 22 Given these findings and previous research suggesting higher rates of complications during winter months, 23 future research may be warranted to investigate clinical outcomes in lung transplant recipients during the winter months. 24 , 25 Nevertheless, it should be duly noted that although dehiscence, pulmonary embolism, and cardiac arrest were statistically significantly more prevalent in Q2-Q4 versus Q1, the prevalence of each of these complications from a clinical standpoint may be less important.…”

Seasonal or cyclical pattern in short-term postoperative outcomes of colorectal cancer? A time series analysis.

“…One of the main causes of postoperative complications are aggravations of coexisting cardiac or respiratory comorbidities and cyclical variations have been shown in the incidence of cardiopulmonary pathologies, mainly during the winter months. Likewise, a cyclical pattern has been suggested for shortterm outcomes of surgery [24][25][26]. It has been reported that postoperative complications in pancreatic or bariatric surgery may present variable incidence, with peak periods of worse outcomes that could show a monthly cyclical pattern [27,28].…”

A Seasonal Variation of Clinical and Neurological Outcomes in Patients with Out-of-Hospital Cardiac Arrest Treated with Extracorporeal Cardiopulmonary Resuscitation: A Secondary Data Analysis of the SaveJ II Study

“…It has been reported that the clinical outcomes of patients with OHCA occurring during the cold season are worse than those in the hot season [ 3 , 4 , 5 ]. Specific diseases (e.g., myocardial infarction, respiratory diseases, and ischemic heart diseases) [ 6 ] that often occur and are complicated by cold conditions may explain the lower survival rates of patients with OHCA in the cold season.…”